Making Nick Silver Can't Sleep
In March 2006 Janice Kerbel talked to Stephen Harris, Druce Curator of Oxford University Herbaria, as part of her background research for Nick Silver Can't Sleep.
Janice Kerbel: I am trying to determine which plants are strictly nocturnal, which have nocturnal properties, and which are nocturnal/diurnal. Is there a known database of plants that are strictly nocturnal? Is there a database of plants with nocturnal properties?
Stephen Harris: No, not as far as I am aware. This material is scattered throughout the literature. The other problem of course is that diurnal properties of plants may change depending on where they are grown. So, a plant may be more or less nocturnal in some parts of the range but not others, particularly if the species is introduced. Nocturnal properties not only include flowering but also leaf movements, e.g. very commonly found in the mimosoid legumes. From the plant’s point of view the important thing is to ensure that the pollen is released and the stigma is receptive. Flower opening is only one part of the reproductive process.
JK: I am searching for plants whose blossoms are open day/night but whose scent is only detectable at night.
SH: Most nocturnal plants will have some scent detectable during the day but this becomes much stronger towards dusk and at night, e.g., species of Nicotiana.
JK: Are there any plants whose nocturnal properties are determined by/parallel with the stages of the moon?
SH: There is no scientific data that I know of on this subject, although there is a lot of folkloric material relating to plants and the phases of the moon.
JK: Do plants have a ‘rest period’ in a 24-hour cycle?
SH: I am not sure what you mean by a ‘rest period’. The other important point of course is that the Circadian rhythm of a plant need not be 24 hours and there is no reason to suppose that all plants have the same ‘internal clock’.
JK: Are there any plants that are believed to be on cycles other than 24-hours?
SH: I do not know of any examples but I don’t see why cycles should not be different between plants, since day length varies between different latitudes.
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Image: Night Blooming Cereus, Selenicereus grandiflorus as Cactus grandiflorus. New illustration of the sexual system of Carolus von Linnaeus and the temple of Flora, or garden of nature, Thornton, R.J., (1807) on Swallowtail Garden Seeds. Creative Commons License and found on Flickr.
